diff --git a/manifests/init.pp b/manifests/init.pp
index 721f0ed..f3ae555 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -17,6 +17,10 @@ class java(
   $version='1.6.0_25-fcs'
 ) {
 
+  validate_re($jre, [ '^true$', '^false$' ])
+  validate_re($jdk, [ '^true$', '^false$' ])
+  validate_re($version, '^[._0-9a-zA-Z:-]+$')
+
   $jre_real     = $jre
   $jdk_real     = $jdk
   $version_real = $version
diff --git a/manifests/jdk_package.pp b/manifests/jdk_package.pp
index 18863ba..2ff72a2 100644
--- a/manifests/jdk_package.pp
+++ b/manifests/jdk_package.pp
@@ -17,7 +17,8 @@ class java::jdk_package (
   $version
 ) {
 
-  # JJM FIXME Validation!
+  validate_re($version, '^[._0-9a-zA-Z:-]+$')
+
   $version_real = $version
 
   package { 'jdk':
diff --git a/manifests/jre_package.pp b/manifests/jre_package.pp
index 7e2b86d..0405a8c 100644
--- a/manifests/jre_package.pp
+++ b/manifests/jre_package.pp
@@ -14,7 +14,8 @@ class java::jre_package (
   $version
 ) {
 
-  # JJM FIXME Validation!
+  validate_re($version, '^[._0-9a-zA-Z:-]+$')
+
   $version_real = $version
 
   package { 'jre':